1. Field
The present disclosure pertains to device identification of devices using characteristics from a physically unclonable function.
2. Background
Physical Unclonable functions (PUFs) provide a mechanism to uniquely identify a hardware device based on intrinsic variations of physical components. When multiple chips are manufactured, the complex semiconductor process introduces slight variations that are beyond the control of the designer. For instance, even if two chips are manufactured from the same silicon wafer, wires designed to be the same will probably differ in width by a few nanometers; microscopic differences in the surface of the silicon will induce almost trivial variations in the curvature of lines. As these unique characteristics are uncontrollable and inherent to the physical device, quantifying them can produce an intrinsic identifier.
However, many devices operate with limited power sources and/or at low power levels (e.g., low voltage). Additionally, such devices may also operate under varying environmental or operating conditions (e.g., temperature variations, etc.). Because PUFs may operate under different power (e.g., voltage) and or environmental (e.g., temperature) conditions, this may affect the characteristic response of the PUF. That is, such voltage and/or temperature variations may change the PUF response, making it difficult to use the PUF for identification purposes.
Aging effects on semiconductor devices may also affect the frequency response of a PUF. For instance, where a PUF includes one or more ring oscillators, the frequency response of the one or more ring oscillators may change over time.
Consequently, there is a need for a method to permit using a PUF for identification purposes even in light of variations that may result from power/voltage and/or temperature variations.